[ovs-dev] [PATCH v2] netdev-dpdk: Refactor the DPDK transmit path.

[Flavio Leitner]

Hi Marko,

On Wed, Jan 13, 2021 at 10:51:03AM +0000, Kovacevic, Marko wrote:
> Hi Flavio,
> 
> > So, I see a small performance gain. Can you provide a more detailed
> > test description? I wonder if we are testing the same thing.
> 
> VSPERF phy2phy_tput uses 2 dpdk pmds and performs zero packet loss test(RFC2544) with bidirectional traffic.

Ok.

> > > and PVP test results are in line with your observations.
> > > NIC: Fortville 10G X710
> > 
> > Great.
> > 
> > > Performance with different traffic profiles when deployed with 32VM's
> > +1M flows + vxlan enabled :
> > > With burst mode : ~1% increase in performance
> > 
> > That is aligned with above.
> > 
> > > as compared to
> > > scatter mode: ~4% decrease in performance.
> > 
> > Hm, that is unexpected. Is this reproducible?
> 
> If you mean are the results reproducible then yes, 
> I done a re-run of v1 and v2 again 

Thanks for checking.

> I ran my test against these commits to get baseline results and then ran v1 and v2 and compared results
> DPDK: b1d36cf82 (HEAD, tag: v20.11, origin/releases) version: 20.11.0
> OVS: 7f79ae2fb (HEAD -> master, origin/master, origin/HEAD) Documentation: Simplify the website main page.
> 
> V1:
> DPDK: b1d36cf82 (HEAD, tag: v20.11, origin/releases) version: 20.11.0
> OVS: 957132b3a (HEAD -> master) netdev-dpdk: Refactor the DPDK transmit path.
> 7f79ae2fb (origin/master, origin/HEAD) Documentation: Simplify the website main page.
> 
> V1: Burst= 1%
> V1: Scatter -4%
> As sunil reported already shows the same results again

Alright. I will try to reproduce in my lab to understand the root
cause.


> As for V2 it didn't show any increase or decrease for both burst and scatter, 
> And even between the v1 and v2 results from my second run it didn't show much difference on my test anyway.
> 
> > How are you switching between burst and scatter mode?
> 
> As for how were switching between burst and scatter, I just use two different traffic profiles & gather results.
> So I run the test using burst profile restart the test then use scatter.
> 
> Traffic @ Phy NIC Rx:
> Ether()/IP()/UDP()/VXLAN()/Ether()/IP()
> 
> Burst: on the outer ip we do a burst of 32 packets with same ip then switch for next 32 and so on 
> Scatter: for scatter we do incrementally for 32 

Glad that I asked because I thought you were talking about the
NIC mode with scatter enabled or not.

> And we do this for 1M flows
> 
> I hope this answers your question

They are helpful. I will try to reproduce the -4% results in my
lab as a next step. It may take some time.

Thanks for testing and providing feedbacks!

-- 
fbl